THE EFFECT OF URINE AND BLOOD METABOLIC RISK FACTORS ON CALCIUM STONE FORMATION

In spite of vast improvements in urinary stone treatment (ESWL, PNL, ureteroscopy, etc.), metabolic workup concerning the existence of stone forming risk factors are of great importance and can lead to control and even prevention of urinary stone formation in these patients. In this analytical case-control study performed on 266 persons [110 normal persons (56 males and 54 females), 76 patients with one episode of stone formation (40 males and 36 females), and 80 patients with recurrent stone formation (40 males and 40 females)] aged between 30 to 45 (with an average of 37.6) in Shahid Doctor Labbafinejad Medical Center from May to July 1999, serum parameters and 24-hour urine parameters have been investigated and compared among the three groups. Results of this study revealed considerable differences in urinary calcium levels of these three groups, with and without considering sex (p<0.05). Averages of 24-hour urinary calcium calculated for normal, one episode and recurrent stone formers in male groups were 159±43, 219± 71, and 283± 74 mg/24h respective1y, and for normal, one episode and recurrent stone formers in female groups were 124±37, 190±58, and 287:t152 mg/24h respectively. Although 24-hour urine citrate in females obviously showed higher values than males, there was no significant difference among the studied groups of the same sex. Levels of serum calcium, potassium and magnesium between groups of females and 24- hour urine magnesium and phosphate levels between groups of males had statistical differences also (p<0.05 for all of the cases mentioned above). According to the results obtained from this study, it was realized that in the studied society levels of 24-hour urinary calcium which are higher than 200 mg/ 24h (sensitivity 80%, specificity 94% and FPR 6.4%) and calcium creatinine ratios of 24-hour urine which are higher than 0.17 (sensitivity 7.5%, specificity 88.1 % and FPR 11.9%) can be regarded as hypercalciuria. However, the results of this study should be confirmed by more general and extended studies.